Grassland Establishment for Wildlife Conservation

D. Todd Jones-Farrand Loren W. Burger, Jr. Department of Fisheries and Wildlife Sciences Department of Wildlife and Fisheries University of Missouri Mississippi State University Columbia, MO 65211 Mississippi State, MS 39762 Email: [email protected] Email: [email protected]

Douglas H. Johnson Mark R. Ryan USGS Biological Resources Discipline Department of Fisheries and Wildlife Sciences Northern Prairie Wildlife Research Center University of Missouri Department of Fisheries, Wildlife, and Columbia, MO 65211 Conservation Biology Email: [email protected] University of Minnesota St. Paul, MN 55108 Email: [email protected]

ABSTRACT Establishing grasslands has important implications for wildlife, especially in areas his- torically rich in grasslands that have since been converted to row crop agriculture. Most grasslands established under farm conservation programs have replaced annual crops with perennial cover that provides year-round resources for wildlife. This change in land use has had a huge influence on grassland bird populations; little is known about its impacts on other terrestrial wildlife species. Wild- life response to grassland establishment is a multi-scale phenomenon dependent upon vegetation structure and composition within the planting, practice-level factors such as size and shape of the field, and its landscape context, as well as temporal factors such as season and succession. Grass- land succession makes management a critical issue. Decisions on how frequently to manage a field depend on many factors, including the location (especially latitude) of the site, the phenology at the site in the particular year, the breeding-bird community associated with the site, and weather and soil conditions. The benefits for a particular species of any management scenario will depend, in part, on the management of surrounding sites, and may benefit additional species but exclude others. Thus, the benefits of grassland establishment and management are location- and species-specific.

Fish and Wildlife Response to Farm Bill Conservation Practices 25 rior to European settlement, prairies and tion. Our best national data on wildlife populations other grasslands covered an estimated 300 exists for birds. Most grassland-nesting birds have P million ha (740 million acres) of the United been experiencing significant population declines States (Risser 1996) and were the largest vegetation for the 37 years of Breeding Bird Survey monitoring type in North America (Samson and Knopf 1994). (Sauer et al. 2004), despite the fact that most grass- Major grassland ecosystems can be classified into land losses occurred before the survey began (Noss et six distinct types based on geography and vegetation al. 1995). Research has documented breeding in the structure: the tallgrass, mixed-grass, and shortgrass Great Plains by 330 of the 435 bird species that breed prairies of the central plains, the desert grasslands in the United States (Samson and Knopf 1994), in- of the Southwest, the California grasslands, and the cluding almost 40 percent of the species on Partners Palouse prairie of the Northwest (Risser 1996). Ad- In Flight’s continental Watch List (Rich et al. 2004). ditionally, subtropical grasslands occurred in Florida Additionally, U.S. grasslands are important winter- and the eastern gulf plain of Texas, and smaller ing habitat for birds of the Northern Forest Avifaunal grasslands occurred in the eastern United States and Biome, which stretches from the northeastern United intermountain west (Rich et al. 2004). States northwest across Canada, as well as grassland Grasslands have been termed the nation’s most breeding birds (Rich et al. 2004). threatened ecosystem (Noss et al. 1995, Samson and The Conservation Reserve Program (CRP) has Knopf 1994). Although they were unable to attain played an important role in stemming the losses data for several states, Sampson and Knopf (1994) of U.S. grasslands. Beginning as part of the Food reported reductions in the U.S. central plains of 82.6 Security Act of 1985 (a.k.a. the 1985 Farm Bill), the percent to 99.9 percent for tallgrass prairies, 30 CRP retired highly erodible cropland for a period percent to 77.1 percent for mixed-grass prairies, and of 10 years. Producers received rental and incentive 20 percent to 85.8 percent for shortgrass prairies. payments to plant perennial vegetation. Most (>75 Reductions for grassland types in other portions of percent) of the 14 million ha (34.8 million acres) en- the country are similar to those of tallgrass prairie, rolled in CRP has been planted to grass or a mixture including California grasslands (99 percent) and the of grasses and forbs or legumes (Table 1). New grass Palouse prairie (99.9 percent) (reviewed by Noss plantings in the continental United States have been et al. 1995). Losses of native grasslands have been established in areas that were historically grassland (and continue to be) primarily due to conversion to (Figures 1-4). Although many conservation practices agricultural or suburban land uses, though woody (CP) may incorporate grass (e.g., permanent wildlife invasion after fire suppression (Rich et al. 2004) and habitat, CP4), seven exclusively establish grass or the planting of trees and other non-native plants in grass-based herbaceous mixtures: new introduced the post-dust bowl era also contributed (Samson and grasses and legumes (CP1), new native grasses (CP2), Knopf 1994). In addition to quantitative losses, grass- grass waterways (CP8), existing grasses and legumes lands have been impacted qualitatively by alterations (CP10), filter strips (CP13 and CP21), contour grass of natural disturbance regimes (fire, grazing pressure, strips (CP15), and cross wind trap strips (CP24). and hydrology) and changes in species composition This manuscript discusses the impact of grass field caused by invasive and non-native species (Rich et al. establishment and management on wildlife species. 2004, Noss et al. 1995, Samson and Knopf 1994). We focus on CRP, specifically CP1 and CP2, because Concomitant with losses and degradation of this program is the primary vehicle for establishment grasslands have been declines of wildlife populations. of grass fields and has been the focus of most of the Disappearance of the massive bison (Bison bison) research into the wildlife impacts of farm conserva- herds from the Great Plains is well known, but many tion practices. Our discussions are valid for CP10 as other grassland species are endangered, threatened these acres are primarily re-enrollments of CP1 and or candidates for listing (e.g. black-footed ferret CP2 fields. Most research has been conducted on (Mustela nigripes), prairie dog (Cynomys sp.), and avian communities in the Great Plains, Midwest, and mountain plover (Charadrius montanus)). There are Southeast. Thus, our discussion of benefits to wildlife many more species for which we lack good informa- necessarily concentrates on birds; we discuss other

26 The Wildlife Society Technical Review 07–1 September 2007 information where available. Discussion of the ben- Nebraska. Analogously, in southeastern Wyoming, efits of other grass-based establishment practices can Wachob (1997) found higher densities of grassland be found in the chapter on linear strips and conserva- birds in CRP fields (as well as in native rangeland) tion buffers. Although the management and spatial than in croplands. In the Midwest, Best et al. (1997) context issues discussed here are equally pertinent to detected from 1.4 to 10.5 times more birds in CRP conservation of rangelands, please see the rangeland grass fields than rowcrop fields during the breeding chapter for a detailed treatment. season. Interestingly, the total number of bird species observed in CRP plantings by Best et al. (1997, 1998) did not differ markedly from the number of species Desired Fish and Wildlife Benefits they observed in nearby rowcrop fields. However, 16 species of birds were unique or substantially more Wildlife conservation was a secondary consideration abundant in CRP fields than in nearby rowcrop of the 1985 Farm Bill but was elevated to co-equal fields. Three of the four bird species they frequently status with erosion and water quality concerns with observed in CRP (dickcissel [Spiza americana], the 1996 re-authorization. Still, it was widely as- grasshopper sparrows [Ammodramus savannarum], sumed that the establishment of CRP plantings would and bobolinks [Dolichonyx oryzivorus]) have been positively affect grassland wildlife populations (e.g., undergoing significant population declines. Addition- Berner 1988), by providing perennial food and cover ally, Henslow’s sparrow (Ammodramus henslowii) resources. In their review of the literature, Ryan et and sedge wren (Cistothorus platensis), species of al. (1998) listed 92 species of birds observed using high conservation concern in the Midwest (Herkert et CRP grass plantings in the central United States dur- al. 1996), occurred only in CRP fields. The Henslow’s ing spring and summer (i.e., the breeding season), sparrow also is listed as a continental Watch List including at least 42 species nesting in CRP. Recent species (Rich et al. 2004). Of the five species unique research has added only one species to that list; or substantially more abundant in rowcrops than in Evard (2000) noted three rough-legged hawks (Buteo CRP fields (Best et al. 1997), only one, the lark spar- lagopus) hunting CRP fields in Wisconsin. Best et al. row (Chondestes grammacus), is of moderate conser- (1998) recorded 40 species using CRP fields in the vation concern in the Midwest (Herkert et al. 1996). Midwest during winter, five of which do not use the Summer observations of ring-necked pheasants fields during the breeding season. Mammals, rep- (Phasianus colchicus) in western Kansas, analyzed tiles, and invertebrates also have been shown to use by Rodgers (1999), showed they used CRP fields CRP grass plantings (reviewed by Farrand and Ryan more than their availability in northwestern Kansas 2005). The benefits provided by planting grass fields but not in southwestern Kansas, where shorter grass can be measured, in part, by the response of wildlife plantings may not provide better habitat than crop- species to the grass relative to the crop land they land. Pheasant indices in Wisconsin CRP fields were replaced. Such benefits are related, in part, to the 10-fold higher than in surrounding private farmland vegetation composition and structure of the plant- (Evard 2000). Johnson and Igl (1995) projected de- ings and how these factors change naturally over time clines in the populations of 15 grassland bird species (i.e., succession). breeding in North Dakota CRP if those grass fields were reverted back to cropland. Retiring Cropland Greater benefits are accrued to those species that breed successfully in planted grass fields than Replacing annual crops with perennial grasses has to those that simply use the fields for food or cover the potential to provide stable cover and food re- (Ryan 2000), because the breeding season is the part sources for wildlife. Indeed, avian studies have shown of the annual cycle that most strongly influences the higher abundances or densities of birds in CRP grass population size of birds. Assessing the reproduc- fields than in the crop lands they replaced. King tive rate is much more challenging than determin- and Savidge (1995) reported avian abundance to be ing population size; grassland birds are notoriously four times greater in CRP fields than crop fields in secretive in their breeding habits. Such behavior is

Fish and Wildlife Response to Farm Bill Conservation Practices 27 Table 1. Summary of grass area and total area in the Conservation Reserve Program by state and the proportion of area in Conservation Practices that establish whole-field grass-based plantings. Numbers presented here reflect conditions as of March 2005.

Statea Grass (ha) Total (ha) %Grass %CP1b %CP2b %CP10b

Alabama 50,949 196,783 25.9 4.0 2.9 92.2 Alaska 11,858 12,066 98.3 19.6 0.0 80.4 Arkansas 15,707 81,813 19.2 7.8 8.0 70.3 California 54,322 58,940 92.2 3.9 1.2 94.9 Colorado 818,246 926,006 88.4 2.4 29.7 67.8 Connecticut 103 129 80.2 27.5 13.3 51.4 Delaware 610 3,134 19.5 3.5 1.5 2.0 Florida 1,019 35,213 2.9 11.8 6.0 82.0 Georgia 3,911 123,457 3.2 5.9 4.0 75.9 Idaho 259,855 319,949 81.2 14.0 3.1 82.7 Illinois 262,128 413,485 63.4 27.7 6.1 38.8 Indiana 91,508 116,681 78.4 16.9 12.6 38.7 Iowa 537,793 773,352 69.5 22.3 11.0 44.2 Kansas 1,046,509 1,161,142 90.1 0.7 31.0 66.8 Kentucky 122,732 136,421 90.0 29.1 12.6 46.1 Louisiana 8,629 98,505 8.8 0.7 11.4 84.8 Maine 8,588 9,436 91.0 6.1 0.5 92.7 Maryland 24,348 34,178 71.2 19.6 5.9 6.9 Massachusetts 47 49 95.9 0.0 0.0 45.7 Michigan 79,886 105,749 75.5 17.3 9.5 51.4 Minnesota 338,672 713,815 47.4 29.3 16.1 35.4 Mississippi 58,624 380,740 15.4 4.0 0.3 90.1 Missouri 574,829 627,322 91.6 25.9 12.9 58.0 Montana 1,234,173 1,376,732 89.6 23.1 27.2 49.7 Nebraska 408,382 483,350 84.5 4.6 35.5 57.6 New Hampshire 70 80 87.8 5.8 0.0 0.0 New Jersey 859 926 92.8 53.5 17.2 21.8 New Mexico 238,503 241,337 98.8 0.2 30.9 68.8 New York 18,589 24,613 75.5 12.8 1.7 84.0 North Carolina 11,735 50,064 23.4 7.8 5.7 62.2 North Dakota 753,405 1,351,363 55.8 21.9 3.5 74.1 Ohio 83,891 112,834 74.3 12.3 13.9 46.5 Oklahoma 407,143 417,669 97.5 1.9 39.0 58.9 Oregon 187,974 204,956 91.7 23.8 11.4 64.2 Pennsylvania 68,800 76,587 89.8 48.3 16.3 33.9 Puerto Rico 186 448 41.5 23.5 0.0 76.5 South Carolina 7,421 85,600 8.7 3.7 0.6 60.9 South Dakota 367,173 593,500 61.9 18.3 25.2 55.6 Tennessee 89,485 110,653 80.9 14.3 18.7 62.6 Texas 1,565,462 1,602,024 97.7 2.8 42.2 54.8 Utah 81,314 81,732 99.5 28.7 7.4 63.8 Vermont 105 626 16.8 0.0 0.0 44.6 Virginia 9,919 25,338 39.1 17.1 11.1 54.8 Washington 478,310 563,134 84.9 10.6 49.2 33.1 West Virginia 299 1,062 28.1 1.4 3.0 89.0 Wisconsin 188,804 251,179 75.2 10.2 12.0 71.8 Wyoming 100,690 113,755 88.5 22.9 3.0 74.1 Undesignated 13 91 14.7 0.0 100.0 0.0 Total (ha) 10,673,588 14,098,018 75.7 13.1 24.8 57.6 Total (ac) 26,363,762 34,822,105

aStates and territories with CRP enrollments. Arizona, Hawaii, Nevada, and Rhode Island did not have enrollments. bConservation Practices that establish whole-field grass-based plantings are: CP1 – new introduced grasses and legumes; CP2 – new native grasses; and CP10 – existing grasses and legumes.

28 The Wildlife Society Technical Review 07–1 September 2007 Figure 1. Land in active CRP contracts in the U.S. and Puerto Rico as of 30 April 2005 for new introduced grasses and legumes (CP1). Disclosure indicates data unavailable due to privacy restrictions required by the Farm Security and Rural Investment Act of 2002.

Practice CP1 (ha) Disclosure 0 1–10,000 10,000–20,000 20,000–30,000 30,000–40,000 40,000–50,000 No CRP Acreage

Figure 2. Land in active CRP contracts in the U.S. and Puerto Rico as of 30 April 2005 for new native grasses (CP2). Disclosure indicates data unavailable due to privacy restrictions required by the Farm Security and Rural Investment Act of 2002.

Practice CP2 (ha) Disclosure 0 1–10,000 10,000–20,000 20,000–30,000 30,000–40,000 40,000–50,000 No CRP Acreage

Fish and Wildlife Response to Farm Bill Conservation Practices 29 Figure 3. Proportion of active CRP contracts in new introduced grasses and legumes (CP1) for the U.S. and Puerto Rico as of 30 April 2005. Disclosure indicates data unavailable due to privacy restrictions required by the Farm Security and Rural Investment Act of 2002.

Proportion CP1 (%) Disclosure 0 0–25 25–50 50–75 75–100 No CRP Acreage

Figure 4. Proportion of active CRP contracts in new native grasses (CP2) for the U.S. and Puerto Rico as of 30 April 2005. Disclosure indicates data unavailable due to privacy restrictions required by the Farm Security and Rural Investment Act of 2002.

Proportion CP2 (%) Disclosure 0 0–25 25–50 50–75 75–100 No CRP Acreage

30 The Wildlife Society Technical Review 07–1 September 2007 necessary to avoid drawing the attention of a wide (Zenaida macroura) in Kansas (Hughes et al. 2000). range of species that depredate nests in grasslands. In Wisconsin, ring-necked pheasant, gray partridge Avian reproductive success has not been well studied (Perdix perdix), northern harrier (Circus cyaneus), in CRP fields in the Great Plains, but the studies that short-eared owl (Asio flammeus), and duck nests have have been conducted indicate that birds, including been reported (Evard 2000). In Missouri, 55 percent several grassland species of conservation concern, are of northern bobwhite (Colinus virginianus) nests and at least as successful in CRP fields as in other land 46 percent of brood-foraging locations occurred in cover types. In northwest Texas, Berthelsen et al. CRP fields that comprised only 15 percent of the large- (1990) found approximately six pheasant nests per ly agricultural landscape (Burger et al. 1994). 10 acres of CRP grassland, but no nests in cornfields. Grass fields also provide important resources for Berthelsen and Smith (1995) found a number of birds in winter. Although Morris (2000) reported nongame bird nests incidental to their upland game- higher species richness in crop fields in southern bird study in Texas. Most common species recorded Wisconsin, she reported lower abundances in crop were red-winged blackbirds (Agelaius phoeniceus), fields than CP2 fields. Avian abundance in crop fields grasshopper sparrows, Cassin’s sparrows (Aimophila was higher during periods of incomplete snow cover cassinii), and western meadowlarks (Sturnella ne- than during periods with 100 percent snow cover, glecta). Nest success values were higher than those while the reverse was true for CP2 sites. Morris typically reported in other studies in the agricultural (2000) did not observe if grassland birds were using Midwest. Koford (1999) found nests of red-winged CP1. However, total bird use in winter did not differ blackbirds, grasshopper sparrows, and savannah between introduced grasses with legumes (CP1) and sparrows to be most common in CRP fields in his switchgrass monocultures (CP2) in Missouri (McCoy North Dakota study sites, while in Minnesota sites et al. 2001a). During the winter months, ring-necked the most numerous species were red-winged black- pheasants, northern bobwhites, American tree spar- birds, bobolinks, grasshopper sparrows, and savan- rows (Spizella arborea), dark-eyed juncoes (Junco nah sparrows (Passerculus sandwichensis). He found hyemalis), and American goldfinches (Carduelis fledging success of ground-nesting birds in CRP fields tristis) were the most abundant or widely distributed was lower than on Waterfowl Production Area plant- species observed in CRP fields (Best et al. 1998). All ings, but not significantly so. but the goldfinch have been undergoing long-term In the Midwest, CRP plantings have been exten- population declines (Sauer et al. 1996). King and sively used for nesting by grassland birds. Murray and Savidge (1995) reported use in Nebraska by American Best (2003) found 20 species nesting in switchgrass tree sparrows, ring-necked pheasants, red-winged (Panicum virgatum) CRP fields in 1999 and 2000 in blackbirds, western meadowlarks, horned larks, Iowa; red-winged blackbirds comprised 56 percent and northern bobwhites. Delisle and Savidge (1997) of the sample. Best et al. (1997) located 1,638 nests noted only American tree sparrows, ring-necked of 33 bird species in CRP fields versus only 114 nests pheasants, and meadowlarks (Sturnella sp.) (eastern of 10 species in a similar area of rowcrops. In row- and western meadowlarks were not distinguishable) crop, they most frequently discovered red-winged wintering on their Nebraska study areas. Burger et blackbird, vesper sparrow (Pooecetes gramineus), al. (1994) provided evidence that CRP plantings in and horned lark (Eremophila alpestris) nests. Nests Missouri provided important winter cover for north- of red-winged blackbirds, dickcissels, and grasshop- ern bobwhites. They documented that 69 percent of per sparrows were the most frequently located in nighttime roosts occurred in CRP fields in an area CRP fields by Best et al. (1997). Similar lists of species where CRP made up only 15 percent of the landscape. nesting in CRP have been produced by recent studies Rodgers (1999) used counts of droppings to compare (Davison and Bollinger 2000, McCoy et al. 2001a). winter pheasant use of weedy wheat stubble and CRP House sparrow (Passer domesticus) was the most in north central Kansas. Despite offering comparable common avian species nesting in CRP fields in north- concealment, dropping density was 2.75 times greater east Kansas (Hughes et al. 2000). CRP also appears in wheat stubble than CRP. Dropping data suggested to be important nesting habitat for mourning doves that pheasants were using CRP for night-time roost-

Fish and Wildlife Response to Farm Bill Conservation Practices 31 ing. CRP may be less valuable to pheasants in winter cidence of cotton pests and found beneficial predator due to fewer food sources, excessive litter, and the species in Texas CRP. Davison and Bollinger (2000) less rigid stems of the planted grass. identified four species of snakes common on their Information comparing mammalian use of planted study sites in east-central Illinois, including prai- grass fields with crop fields is scarce, and informa- rie kingsnake (Lampropeltis calligaster), common tion on reproductive activity is virtually non-existent. garter snake (Thamnophis sirtalis), black rat snake Olsen and Brewer (2003) reported that a three-year, (Elaphe obsoleta obsoleta), and blue racer (Coluber winter wheat (Triticum aestivum) rotation in south- constrictor). Hughes et al. (2000) listed bullsnakes eastern Wyoming had higher rodent abundance and (Pituophis melanoleucus) as a potential nest preda- diversity than CRP at both sites in both years studied. tor in Kansas CRP. A study of white-tailed deer (Odocoileus virginianus) habitat use in South Dakota revealed that CRP fields Planting Perennial Vegetation were used proportionately greater than habitat avail- ability during periods of deer activity during spring, Wildlife response to changes in land use is species- and during evening and midnight periods during specific, depending on life-history requirements. summer (Gould and Jenkins 1993). Thus, issues regarding the composition of the plant- Increased use of CRP between ing (e.g., introduced or native species, monoculture of spring and summer corresponded grass or a mixture of grasses and forbs/legumes, seed- with rapid vegetation growth and ing rate, etc.) and its resultant structure (e.g., height, fawning. Similarly, white-tailed plant density) will play an important role in determin- deer in southeastern Montana used ing what species can benefit from the practice. CRP in greater proportion than its The primary farm conservation practices that availability in all seasons except fall establish new grass fields are CP1 (introduced grasses (Selting and Irby 1997). Indirect and legumes) and CP2 (native grasses). As the names evidence of mammalian use of CRP suggest, the primary difference between the two is the Dickcissel. (Photo by comes from the nest predation lit- origin of grass and legume seed. Either practice can S. Maslowski, USFWS) erature. Hughes et al. (2000) listed be planted as a grass monoculture or as a mixture of potential nest predators at their grasses with or without forbs and/or legumes; eligible sites in Kansas, including coyotes plant lists are developed by individual states. Each (Canis latrans), raccoons (Procyon planting must conform to NRCS Practice Standard 327 lotor), striped skunks (Mephitis – Conservation Cover (NRCS 2002). The standard sets mephitis), opossums (Didelphis forth base criterion for each establishment including: virginiatum), feral cats (Felis minimum seeding rates; guidelines for the seeding domesticus), and badgers (Taxidea rate, seedbed preparation, and companion crops; and taxus). Evard (2000) attributed management considerations. The standard also in- duck nest predation to mammalian cludes “Additional Criteria for Enhancement of Wild- predators, including red fox (Vulpes life Habitat,” which gives guidelines related to plant vulpes), striped skunk, and raccoon, selection, native forb establishment, an adjustment Red-winged Blackbird. (Photo by though hard evidence was lacking. factor (0.75) to reduce seeding rates if erosion control D. Dewhurst, USFWS) Other mammalian species inciden- guidelines can still be met, and maintenance recom- tally noted in CRP included white-tailed jackrabbits mendations. The combination of the practice standard (Lepus townsendii), white-tailed deer fawns, and a with the individual land owner’s conservation plan coyote den with three pups (Evard 2000). yields flexibility to meet the land owner’s needs and As with mammals, information on benefits ac- variability in the practice’s wildlife habitat value. crued to other groups of wildlife is rare. Burger et al. Few studies have directly compared avian re- (1993) reported mean invertebrate abundance and sponse to CP1 and CP2 plantings. McCoy et al. biomass in CRP fields were four times higher than in (2001a) found that species richness, abundance and soybean fields. Phillips et al. (1991) detected a low in- nesting success of grassland birds during the breed-

32 The Wildlife Society Technical Review 07–1 September 2007 ing season did not differ between CP1 (introduced niles, only 1 of 1,204 locations was recorded in a CRP grasses and legumes) and CP2 (switchgrass mono- field. The authors believed this was due to the taller, cultures) in Missouri. However, species-specific denser vegetation of CP1 (introduced warm-season Mayfield nest success often differed between CP1 grass plantings) compared with the native short grass and CP2 within years, and the better type switched prairie preferred by swift foxes. between years in several cases. However, means dif- Several studies have focused on invertebrate re- fered only for red-winged blackbird. Parasitism rates sponse to CP1 and CP2 plantings. Burger et al. (1993) did not differ between the practices for any species, reported that CP1 fields planted to timothy (Phleum but varied with host species (mean=18%, range 0- pretense) and red clover (Trifolium pretense) had 40%). Fecundity of dickcissel, a continental Watch significantly higher invertebrate abundance and List species (Rich et al. 2004), and nesting success biomass than CP1 or CP2 grass monocultures or CP1 and fecundity of red-winged blackbirds were higher fields planted orchard grass (Dactylis glomerata) on CP2 than on CP1 habitat, but both practices were and Korean lespedeza (Kummerowia stipulacea). likely sinks (λ < 1) for these species. For grasshopper Carroll et al. (1993) determined CRP grasses (native sparrows, a species of national concern (Rich et al. and exotic) to be marginal over-wintering habitat for 2004), nest success was 49 percent in CP2 compared boll weevils (Coleoptera: curculionidae) in Texas. with 42 percent in CP1. Both practices were likely Also in Texas, McIntyre and Thompson (2003) source (λ > 1) habitat for grasshopper sparrows, reported that CP1 and CP2 fields had less vegetative whereas only CP1 fields were likely a source for east- diversity and lower arthropod diversity than native ern meadowlarks (Sturnella magna) and American shortgrass prairie, but did support avian prey groups. goldfinches (McCoy et al. 2001a). The CRP types were similar in terms of invertebrate Morris (2000) compared winter use by grassland abundances (i.e., no support that different types of birds of CRP, crop fields, pastures, and restored and grasses possess different prey availabilities for grass- native prairies in southern Wisconsin. In this study, land birds). In a concurrent study, McIntyre (2003) species diversity was highest in crop fields, followed surveyed CP1, CP2 and native shortgrass prairie in by restored prairie, CP2 fields (a mixture of native the Texas panhandle for endangered Texas horned warm-season grasses and two forbs), native prairie lizards (Phrynosoma cornutum) and their food remnants, and pastures, while avian abundance was supply, harvester ants (Pogonomyrmex). Ant nest highest in pastures, followed by restored prairie, densities varied within the classes but not between, CP2, crop fields, and native prairie. No species were suggesting that planting type (exotic vs. native) did observed using CP1 fields (a mixture of introduced not affect habitat value. Lizards also were seen on grasses and legumes) in this study. In contrast, Mc- both types of CRP, but only at sites with ant nests. Coy et al. (2001a) found that total bird use in the win- Several studies investigated the effect of forb ter did not differ between CP1 and CP2 in Missouri. abundance on wildlife response. Hull et al. (1996) Although we know of no studies directly examining examined the relationship between avian abun- mammalian response to CP1 versus CP2, two studies dance and forb abundance in native-grass CRP have compared CP1 fields to native prairies. Hall and fields in northeast Kansas. The expected signifi- Willig (1994) found that CP1 fields simulated short- cant relationship was not found, but no field had grass prairies of northwest Texas in small mammal > 24 percent forbs, which the authors surmised diversity but not in species composition, suggesting was too low to produce a response. Their data also that CRP was not mimicking natural conditions. Of did not support the hypothesis that invertebrate the 11 species captured in the study, only the south- biomass was correlated positively with forb abun- ern plains woodrat (Neotoma micropus) was not cap- dance. However, Burger et al. (1993) concluded that tured on CRP. Also in northwest Texas, Kamler et al. planting legumes may improve CRP plantings for (2003) reported that both adult and juvenile swift fox northern bobwhite brood-rearing habitat due to in- (Vulpes velox) strongly avoided CP1 fields. Whereas creased invertebrate biomass. Swanson et al. (1999) CRP comprised 13 percent of the available habitat for reported that savannah sparrows used fields with adults and 15 percent of the available habitat for juve- less forb canopy cover.

Fish and Wildlife Response to Farm Bill Conservation Practices 33 Vegetation Succession older fields, while relative abundance increased with age. Millenbah (1993) reported greater insect abun- Although the initial planting mixture and density is dance on one- to two-year-old fields, which may have important, changes in structure will occur over time. contributed to greater small mammal diversity on McCoy et al. (2001b) studied vegetation changes these age classes. Conversely, Hall and Willig (1994) on 154 CRP grasslands in northern Missouri and detected no significant differences in mammalian reported that during the first two years following diversity due to age of CP1 plantings. However, their establishment, fields are characterized by annual sites were only one to three years post-planting weed communities with abundant bare ground and compared with Furrow’s one- to six-year-old sites. little litter accumulation. Within three to four years, Furrow (1994) also surveyed mid-sized mammals CRP fields became dominated by perennial grasses using scent stations and noted a decreasing trend in with substantial litter accumulation and little bare detections with increasing age of the CRP field. The ground. They suggested that vegetation conditions decreasing trend was attributed to decreases in ease three to four years after establishment might limit the of movement and prey diversity. value of enrolled lands for many wildlife species and some form of disturbance, such as prescribed fire or disking, might be required to maintain the wildlife Principles for Application habitat value of CRP grasslands. Few studies have examined avian response to Wildlife habitat selection and use is a multi-scale field age. In an analysis of Breeding Bird Survey data phenomenon (e.g., Gehring and Swihart 2004, Best combined with CRP contract data, Riffell and Burger et al. 2001, Johnson 1980). In addition to the within- (2006) showed the abundances of northern bobwhite field factors (vegetation composition, structure, and and common yellowthroat were positively correlated succession) described above, response to implemen- with the density of CRP fields <4 years old. Eggebo et tation of a particular planting is dependent upon al. (2003) observed more crowing pheasants in old, practice-level factors (e.g., size, shape), the landscape cool-season, CRP fields than any other age or cover context in which those plantings are placed (e.g., to type in South Dakota. Delisle and Savidge (1997) what extent are alternative grasslands available), and noted that grasshopper sparrow densities declined in how the fields are managed over time. the CRP fields in Nebraska each year of their study from 1991 to 1994. They attributed that change to a Field Size, Shape and Landscape Context build-up of litter and dead vegetation. Swanson et al. (1999) evaluated avian use of two- to seven-year-old The size of a grassland patch and its surrounding CRP (CP1, CP2 and CP10) fields in Ohio and reported landscape can markedly influence the use of that site that neither species richness nor total abundance was by grassland birds. Some patches may be too small related to field age. However, these coarse summary to be colonized by certain species, or birds using metrics may mask shifts in community composition smaller patches may suffer more from competition (Nuttle et al. 2003). or predation than do birds in larger patches. Also, As with birds, little information exists on mamma- smaller patches have a relatively greater proportion lian response to aging fields. Furrow (1994) captured of their area near an edge, so edge effects can be more eight small mammal species on CRP fields planted pronounced in smaller patches. Edge effects are phe- to exotic grasses (CP1) in Michigan. Deer and white- nomena such as avoidance, predation, competition, footed mice (Peromyscus spp.) dominated younger or brood parasitism that operate at different levels fields and meadow voles (Microtus pennsylvani- near a habitat edge than in the interior of a habitat cus) dominated older (>2 years) fields. Peromyscus patch (e.g., Faaborg et al. 1993, Winter and Faaborg numbers were positively correlated with bare ground 1999). Brown-headed cowbirds (Molothrus ater) are and forb canopy cover, and voles were positively brood parasites; they lay their eggs in nests of other correlated with litter depth. Fields <2-years-old had birds and leave them for the host birds to raise, usu- a greater diversity of small mammalian species than ally to the detriment of the host’s own young. Cow-

34 The Wildlife Society Technical Review 07–1 September 2007 birds use elevated perch sites to find nests to parasit- McCoy (2000) compared measures of grassland ize; such perches are more frequent along edges of bird use and habitat quality between CRP fields grasslands because of the presence of trees, fence located in landscapes with high (20-35 percent) or posts, and the like. Isolation from other grassland low (5-12 percent) amounts of CRP and high (55-75 patches is a landscape feature that can affect either percent) or low (20-35 percent) amounts of grass- the use by birds or the fate of their nests in a patch. land. Dickcissels and sedge wrens were more likely Each of these factors—patch size, amount of edge, to be present in CRP fields in landscapes with higher and isolation—can affect 1) the occurrence or density levels than lower levels of CRP. Total species rich- of birds using a habitat patch; 2) reproductive success, ness was highest in high CRP, high grassland land- through either predation rates or brood parasitism scapes, and total bird abundance was higher in high rates; or 3) competition with other species (Johnson grassland than low grassland landscapes, but there and Winter 1999, Johnson 2001). These features were no similar effects for grassland birds as a group. have been shown to operate among several species of Nesting success was higher for wild turkey (Melea- grassland birds (e.g, Herkert et al. 2003; Winter et al. gris gallopavo) in high grassland than low grassland In press; reviewed by Johnson 2001). In CRP habitat landscapes, and was higher for red-winged blackbirds specifically, Johnson and Igl (2001) related the occur- in high CRP than low CRP landscapes. rence of species and their densities to patch size in CRP Best et al. (2001) investigated the effect of land- fields. They conducted 699 fixed-radius point counts scape context, including proportion in CRP, on avian of 15 bird species in 303 CRP fields in nine counties use of rowcrop fields in Iowa. Some species showed a in four states in the northern Great Plains. Northern strong response to landscape composition (including harriers, sedge wrens, clay‑colored sparrows (Spizella dickcissel and indigo bunting [Passerina cyanea]), pallida), grasshopper sparrows, Baird’s sparrows (Am- while others did not (e.g., American robin [Turdus modramus bairdii), Le Conte’s sparrows (Ammodra- migratorius], American goldfinch, and killdeer mus caudacutus), and bobolinks were shown to favor [Charadrius vociferus]). Seven species differed larger grassland patches in one or more counties. In significantly between landscapes; for these the lowest contrast, two edge species, mourning doves and brown- numbers in crop fields occurred in areas of intensive headed cowbirds, tended to favor smaller grassland agriculture. Species with different habitat affinities patches. Horn (2000) sampled 46 CRP fields in North (grass or wood) showed similar aversion to rowcrops. Dakota during 1996 and 1997. He reported bobolinks, Grassland birds occurred more often in landscapes grasshopper sparrows, and red-winged blackbirds with more grass (block or strip). Generalists, crop were more common in large grassland patches than in specialists, and aerial foragers were not affected by smaller ones. In contrast, brown-headed cowbirds pre- landscape composition. ferred smaller fields. Field size also was an important Merrill et al. (1999) compared landscapes (1.6-km ra- factor influencing the occurrence and/or abundance of dius) surrounding greater prairie-chicken leks with ran- grassland songbirds in switchgrass plantings in Iowa dom non-lek points and found greater amounts of CRP (Horn et al. 2002). In southeastern Wyoming, Wachob in the landscape for leks. Toepfer (1988) documented (1997) noted that sharp-tailed grouse favored larger nesting in Minnesota CRP, but success was lower in CRP patches for nesting but not for brood-rearing. CRP than in native grasslands (J. Toepfer, unpublished Conversely, Rodgers (1999) postulated that pheas- data, in Merrill et al. 1999). The shape of grassland and ants in western Kansas had not benefited from CRP as woodland patches was significant but had low predic- much as expected due to the large size of the plantings. tive power for comparisons between temporary and Use of CRP (CP1, CP2 and CP10) fields by several traditional leks. Merrill et al. (1999) believed CRP might grassland-dependent species in Ohio was related to be important, especially near temporary lek sites. Sve- field size (eastern meadowlarks and bobolinks) or darsky et al. (2000) recommended that 30 percent of field size plus adjacent grasslands (grasshopper spar- the grassland surrounding greater prairie-chicken leks rows) (Swanson et al. 1999). All species recorded in be managed to provide spring nesting cover and be in this study were more abundant in CRP fields contigu- close proximity to brood cover to maintain populations. ous with other grassland. Wachob (1997) noted that sharp-tailed grouse leks were

Fish and Wildlife Response to Farm Bill Conservation Practices 35 more common closer to CRP fields and in areas with lifespan of the contract. Successional changes can extensive CRP within 0.6 mile (1 km). be mitigated through management practices such as Recent studies have examined the landscape scale mowing, disking, burning, or herbicide applications. effects of CRP across large regions. Riffell and Burger Until the 2002 reauthorization, grazing and haying (2006) examined the abundances of 15 bird spe- were not permitted practices under the CRP, except cies associated with grasslands in the eastern United during weather-related emergencies (e.g., drought). States and found positive correlations between bird All management practices effect wildlife populations abundance and amount of CRP in the landscape. Bird indirectly through changes in vegetation structure, responses varied by species and by ecological region, but also directly as a potential cause of mortality. but tended to be stronger in regions where grasslands Mowing or clipping is the most common manage- were relatively scarce. Similarly, Veech (2006a) inves- ment practice implemented on CRP grasslands. Mc- tigated the relationship between northern bobwhite Coy et al. (2001b) reported that mowing had short- population trends and land use across its range. He term effects on vegetation structure (reduced height found that landscapes with increasing populations within the year and increased litter accumulation) had significantly more useable land (e.g., cropland and resulted in accelerated grass succession and litter and grassland). In a separate analysis, Veech (2006b) accumulation. Dykes (2005) characterized vegetation examined the population trends of 36 grassland nest- structure on 45 CP2 fields in Tennessee and reported ing birds in the Midwest and Great Plains relative to that litter cover and depth were greater on fields that land use. Restored grasslands (e.g., CRP) were typi- had been mowed than those that had been burned. cally rare, but were more common in landscapes with Litter cover and depth were intermediate on unman- increasing than decreasing populations. aged fields. Conversely, forb coverage was greatest on In contrast to these studies, Hughes et al. (2000) burned fields, followed by unmanaged and mowed found that mourning dove Daily Survival Rate (DSR) fields (Dykes 2005). was influenced by vegetation structure within the field, Effects of mowing and haying on wildlife have but not field edge or landscape (800 m) factors. Land- been fairly well studied. These effects can be divided scape effects were thought to be lacking due to the according to temporal category: immediate, short- generalist nature of doves. For ring-necked pheasants term, and long-term. Immediate effects usually in northwestern Kansas, the amount of CRP in areas include the destruction of nests that are active in the where home ranges were located had no detectable field at the time, fatalities of nesting adults or de- effect on size of home ranges (Applegate et al. 2002). pendent young, and abandonment of nests or breed- Females tended to have smaller home ranges (average ing territories that had been established in the field of 127 ha) in high-density (25 percent) CRP sites than (Rodenhouse and Best 1983, Warner and Etter 1989, low-density (8 to 11 percent) CRP sites (average 155 Bollinger et al. 1990, Frawley and Best 1991, Dale et ha), but males showed the reverse trend. Horn et al. al. 1997, McMaster et al. 2005). For example, Labisky (2002) also found no effect of landscape on the rela- (1957) observed that 78 percent of mallard (Anas tions between avian occurrence, abundance, and field platyrhynchos) and blue-winged teal (Anas discors) size. They noted that the literature is contradictory nests in alfalfa fields were destroyed by haying. In concerning landscape effects on area sensitivity and their study of bobolinks (Dolichonyx oryzivorus), postulated that the amount of woodland cover, ranges Bollinger et al. (1990) found that mowing accounted in field sizes among landscapes, and amounts of shrub for 51 percent direct mortality in active nests. Sub- and forb cover within CRP fields may have confounded sequent causes of mortality in eggs and of nestlings any relationship with landscape composition. included abandonment after mowing (24 percent), raking and baling (10 percent), and predation (9 per- Management Practices cent); only 6 percent of the clutches fledged success- fully. In addition, removal of the vegetation by haying As previously mentioned, plant communities on exposes surviving birds, especially young ones, to CRP grasslands are not static, but rather change in greater predation pressure (e.g., George 1952, Bol- species composition and structure over the 10-year linger et al. 1990).

36 The Wildlife Society Technical Review 07–1 September 2007 To mitigate these immediate effects, USDA Horn and Koford (2000) reported fewer sedge prohibits regular management activities in CRP wrens and, possibly, clay-colored sparrows, Le Con- grasslands during a set “Nesting Season”; emer- te’s sparrows, and red-winged blackbirds in mowed gency management is also affected. The start date, than in uncut portions of 12 CRP fields (in North end date, and length of this restricted period vary Dakota) in the year after mowing. Savannah sparrows from state to state (even by county within some and possibly grasshopper sparrows showed the oppo- states) based on consultations between USDA and site tendency, being more common in mowed CRP. USFWS. A table containing these dates, as well as McCoy et al. (2001a) examined the influence of permissible periods for management under the new mowing on birds wintering in CRP fields in Missouri. Managed Haying and Grazing provision of the 2002 They noted that mowing of cool-season CRP plant- Farm Bill, can be found on the Internet (www.fsa. ings in late summer and early fall permitted sufficient usda.gov/dafp/cepd/crp/nesting.htm). Restricting regrowth to provide habitat for wintering birds. In management activities to outside the peak nest- contrast, the value of mowed warm-season planting ing period likely has a positive impact on nesting was reduced for at least two years. success of grassland birds. However, the benefit of As might be expected, birds that prefer heavy this restriction to populations has not been evalu- cover for nesting typically prefer uncut vegetation. ated and may be limited by annual fluctuations in For example, Oetting and Cassel (1971) reported that the timing of peak nesting with annual weather significantly more ducks nested in unmowed stretch- patterns, inability to protect late-season nesting/re- es of roadside right-of-way than in adjacent mowed nesting attempts, and a general lack of attention stretches. Also, Renner et al. (1995) found that the among researchers and managers to the habitat density of nests of five species of ducks was lower in needs of post-fledgling birds. portions of CRP fields that had been hayed the previ- We consider short-term effects to be those that ous year than in the uncut portions. Overall, densi- manifest within about a year after the management ties were twice as high in the uncut vegetation. The action. Johnson et al. (1998) assessed densities of earliest nesting species, mallard and northern pintail, breeding birds in hayed versus idled grassland that especially avoided the hayed portions until sufficient had been restored under the Conservation Reserve regrowth had occurred. Analogously, Luttschwager et Program the year after haying occurred. Because the al. (1994) observed a shift in the species composition authors used the same fields in all years, they had from mostly mallards in uncut CRP field to primarily essentially a before-and-after, treatment-and-control blue-winged teal in hayed CRP fields. design. They had data from nearly 300 fields that It is worth mentioning here that grazing may in- had been hayed and more than 2,600 fields that had creasingly be used as a management technique under been left idle in the previous year; study fields were the new Managed Haying and Grazing provision of in eastern Montana, North Dakota, South Dakota, the 2002 Farm Bill. Because grazing of CRP histori- and western Minnesota. Three species typically had cally has been restricted to emergency situations heightened densities the year following haying; these (e.g., drought conditions), little direct information is were horned lark, chestnut-collared longspur, and available. Whereas there has been much research on lark bunting, all of which favor short and sparse grazing and birds in rangeland systems, the results vegetation. The densities of many more species, in are often contradictory (see Ryan et al. 2002 and contrast, were reduced the year following haying, references therein). In general, grazing, like mowing including vesper sparrow, sedge wren, common yel- and haying, can negatively impact wildlife directly lowthroat, bobolink, clay-colored sparrow, dickcissel, or indirectly. Direct effects may include trampling red-winged blackbird, and Le Conte’s sparrow. Some and exposure due to reduced vegetation structure. species had responses that varied by study site (and Indirect effects may include increased exposure associated climatic regime). Savannah, grasshopper, (thermal) and predation due to vegetation removal and Baird’s sparrows tended to respond negatively and composition shifts. However, grazing does not to mowing in the more arid western study sites but impact all birds negatively. Reduced structure may positively in study sites with greater precipitation. prompt some birds to avoid grazed pastures, but at-

Fish and Wildlife Response to Farm Bill Conservation Practices 37 tract other species. Grazing impacts are complex and up) treatments on bobwhite brood habitat quality depend upon the species under consideration, graz- in fescue-dominated, idle grass fields in Kentucky. ing regime (i.e., grazing intensity, timing, frequency, They reported that during the first growing season and the livestock species), and other biotic and following treatment, fall disking significantly en- abiotic factors (Ryan et al. 2002). As noted above, hanced brood habitat quality by increasing insect USDA attempts to mitigate direct effects of grazing abundance, plant species richness, forb coverage, through timing restrictions, but the benefit of such and bare ground relative to control plots. However, restrictions is difficult to guage. the benefits of disking were relatively short-lived, Although our focus has been on breeding birds, with diminished response during the second growing there is some relevant information on other taxa, season. During the second growing season follow- specifically some mammals. For example, West- ing treatment, herbicide treatments provided the emeier and Buhnerkempe (1983) noted that nests of best brood habitat quality. Greenfield et al. (2002), small mammals (Microtus ochrogaster and Synap- examining the effects of disking, burning, and herbi- tomys cooperi) and cottontail rabbits (Sylvilagus cide on bobwhite brood habitat in fescue-dominated floridanus) were most abundant in prairie grasses CRP fields in Mississippi, likewise reported that left undisturbed, indicating that they would respond disking and burning improved vegetation structure negatively to haying. Leman and Clausen (1984) also for bobwhite broods during the first growing season commented that meadow voles (Microtus pennsyl- after treatment. However, the benefits were short- vanicus) and prairie voles (M. ochrogaster) were lived (one growing season). Herbicide treatment in significantly less common on plots with lower re- combination with prescribed fire enhanced quality sidual vegetation; those plots were the ones mowed of bobwhite brood habitat for the longest duration most recently. In contrast, deer mice (Peromyscus (Greenfield et al. 2002). maniculatus) were more common on the most re- cently mowed plot. By long-term effects, we refer to those occur- Concerns or Opportunities ring more than a year afterward. In addition to the above finding by McCoy et al. (2001) about The CRP was amended in the 2002 reauthoriza- effects persisting at least two years, Johnson et al. tion to require mid-contract cover management (1998) discovered delayed responses to haying of (i.e., incorporating native seeds, light disking, and CRP fields. Some species, such as lark bunting, Le burning) on all new covers under new contract Conte’s sparrow, and clay-colored sparrow, showed (USDA 2003). Additionally, the original provi- a response in the second year after haying that was sion prohibiting commercial uses of CRP lands was similar to, albeit weaker than, the response in the amended to allow managed haying and grazing, as first year. Although the response by horned larks well as biomass harvests and the installation of wind to haying was positive rather uniformly in the first turbines. Whereas managed haying and grazing was year, responses in the second year varied geographi- specifically restricted to one in three years, no fed- cally, being negative in the drier, western study sites eral guidelines were issued for biomass harvests and but positive in the more mesic eastern sites. Sedge cover management practices. wrens, reduced the first year after haying, tended to Grasslands are disturbance-dependent ecosystems, increase the second year. Several species, including so it is natural to consider the role of disturbance in common yellowthroat, red-winged blackbird, and established grasslands compared with natural prairies. bobolink, showed no consistent pattern two years Grasslands evolved with, and indeed were maintained after haying, despite broadly negative responses the by, fire and grazing. Fire was especially important in first year after haying. eastern prairies and the tallgrass prairie, where fre- Our knowledge on the effects of other manage- quent—often annual—fires restricted the encroachment ment practices is limited. Madison et al. (1995) of woody vegetation. In western prairies especially, examined the effects of fall, spring, and summer bison (Bison bison) and other native grazers main- disking and burning, and spring herbicide (Round- tained viable grasslands. Mowing, haying, and disking

38 The Wildlife Society Technical Review 07–1 September 2007 are disturbances that are now common in agricultural for a wider array of species. Decisions on how fre- settings but did not occur naturally. It is reasonable quently to manage a field depend on many of the to contemplate if and how those activities should be same factors as for the establishment of haying dates used in establishing and maintaining grasslands. In discussed above. For example, as a result of longer our view, human disturbance of established grasslands growing seasons and greater rainfall, the rate of that mimics the natural disturbance regimes will better natural succession on CRP grasslands throughout the provide for species that evolved with grasslands. Southeast likely exceeds that observed in the Midwest Mandated disturbance will address some short- or Great Plains, making planned disturbance even comings of CRP grasslands as wildlife habitat but also more important for maintaining habitat quality for raise some concerns. Management practices such as early successional species. burning and grazing may mimic natural disturbances, Although USDA (2003) contends that wind tur- especially if used in combination. By removing veg- bines “generally have a limited impact on wildlife,” etation, these practices are likely to benefit grassland their impact may be dependent on placement (e.g., bird species associated with shorter, sparser grass- near migratory routes) and species-specific suscep- lands. If these practices occur in a patchy distribu- tibilities. Avian mortality at wind farms appears to tion within a field, across the landscape, and through be low relative to the number of birds passing over time, a mosaic of grassland successional stages may them, or to communication towers and other tall form that can sustain a wider array of species. How- structures (see Johnson et al. 2002 and references ever, if a uniform management is applied to most therein). However, turbines may add to the cumula- fields in a landscape (i.e., the same practice applied to tive declines of some species. Wind farms appear to whole fields at the same time of year and in the same have very little effect on resident bats in Minnesota years), conservation goals for a wide range of species (Johnson et al. 2004) and Iowa (A. A. Jain, unpub- will not be accomplished. lished data). However, substantial numbers of mi- CRP management can only be applied according grating bats suffered collision deaths in both studies. to a detailed conservation plan (USDA 2003). We More study is needed to fully understand the impacts recommend such plans carefully consider the timing of wind turbines on wildlife. of management actions. From a purely agricultural perspective, grasses and associated forbs should be harvested at or near the peak of their nutritional Links with Other Systems quality. That strategy conflicts with providing habitat for nesting birds. The immediate effects of haying Grasslands established under CRP, or any other are extremely detrimental, of course, but they can program, are linked to varying degrees with other be largely avoided by delaying haying until after the systems in the landscapes in which they are embed- bulk of nesting activities has ceased. Establishing a ded. Perhaps the closest and most important linkage reasonable date to begin haying depends on many is with riparian and aquatic systems. As mentioned factors, including the location (especially latitude) in the introduction, CRP was originally targeted at of the site, the phenology at the site in the particular highly erodible soils to improve and protect water year, the breeding-bird community associated with quality. CRP continues to provide those benefits the site, and weather conditions. Similarly, these fac- through regular sign-ups and extensions of the tors need to be considered when planning the timing program targeted at high value conservation (i.e., and length of grazing. Other management practices, Conservation Reserve Enhancement Program). such as burning, disking, and harvesting biomass CRP grasslands tend to be established in landscapes for energy (e.g., co-firing switchgrass with coal) can already containing more grassland and woodland generally be done outside the nesting season and areas (Weber et al. 2002), likely because these areas therefore pose less of a dilemma. tend to have higher slopes and are more difficult to Another consideration is the frequency of manage- farm than relatively flat areas. These areas also pres- ment. Irregular management will result in a greater ent higher risk to aquatic systems from agricultural variety of grassland successional stages and provide runoff of sediment, nutrients, and chemicals. The

Fish and Wildlife Response to Farm Bill Conservation Practices 39 Farm Service Agency is currently funding projects mowing it in May. Vegetation will recover from mow- to estimate the water quality benefits provided by ing much more quickly when soil moisture is high CRP practices in various regions of the country (S. than when it is not. Further, management scenarios Hyberg, personal communication). that benefit one species will benefit some others but also exclude some. These considerations lead to the conclusion that a “one size fits all” approach to man- Conclusions aging grasslands will not work.

Establishing grasslands has important implications for wildlife, especially in areas historically rich in grasslands that have since been converted to row Literature Cited crop agriculture. Most grassland established under farm conservation programs has replaced annual Applegate, R. D., B. E. Flock, P. S. Gipson, M. W. McCoy, and crops with perennial cover that provides year-round K. E. Kemp. 2002. Home ranges of ring-necked pheasants in northwestern Kansas. Prairie Naturalist 34:21-29. resources for wildlife. Which wildlife species benefit Best, L. B., H. Campa, III, K. E. Kemp, R. J. Robel, M. R. Ryan, from grassland establishment depends on many fac- J. A. Savidge, H. P. Weeks, Jr., and S. R. Winterstein. 1997. tors at multiple spatial and temporal scales. These Bird abundance and nesting in CRP fields and cropland in the Midwest: a regional approach. Wildlife Society Bulletin factors include within-field factors (vegetation com- 25:864-877. position, structure, and succession), practice-level Best, L. B., H. Campa, III, K. E. Kemp, R. J. Robel, M. R. Ryan, factors (e.g., size, shape), the landscape context in J. A. Savidge, H. P. Weeks, Jr., and S. R. Winterstein. 1998. Avian abundance in CRP and crop fields during winter in which those plantings are placed (e.g., to what extent the Midwest. American Midland Naturalist 139:311-325. additional grasslands are available), the season or life- Best, L. B., T. M. Bergin, K. E. Freemark. 2001. Influence of cycle stage the species uses the grassland for, and how landscape composition on bird use of rowcrop fields. Jour- nal of Wildlife Management 65:442-449. the fields are managed over the life of the contract. Berthelsen, P. S., and L. M. Smith. 1995. Nongame bird nesting Periodic management, especially practices that on CRP lands in the Texas Southern High Plains. Journal of profit land owners, is a relatively new mandate for Soil and Water Conservation 50:672-675. established grasslands. It can be argued that as dis- Berthelsen, P. S., L. M. Smith, and R. R. George. 1990. Ring- necked pheasant nesting ecology and production on CRP turbance-dependent systems, grasslands should be lands in the Texas southern High Plains. Transactions of manipulated periodically. Such disturbances, how- the North American Wildlife and Natural Resource Confer- ever, should occur no more often than is necessary; ence 55:46-56. Berner, A. H. 1988. The 1985 Farm Act and its implications the frequency depends on factors such as precipita- for wildlife. Pages 437-466 in W. J. Chandler, editor. tion and species composition of the plants. It should Audubon wildlife report 1988/1989. Academic Press, San be remembered that the response by breeding birds Diego, California, USA. Bollinger, E. K., P. B. Bollinger, and T. A. Gavin. 1990. Effects to such disturbances will depend on the location of hay-cropping on eastern populations of bobolink. Wild- of the site relative to the breeding ranges of vari- life Society Bulletin 18:142-150. ous bird species, the habitat preferences of species Burger, L. W., Jr., E. W. Kurzejeski, T. V. Dailey, and M. R. Ryan. 1993. Relative invertebrate abundance and biomass in whose ranges encompass the site, the environmental Conservation Reserve Program plantings in northern Mis- conditions—especially soil moisture—prevailing, and souri. Pages 102-108 in K.E. Church and T. V. Dailey comm. the timing of the disturbance. For example, Baird’s editors. Quail III: National Quail Symposium. Missouri sparrows prefer grassland habitat with moderately Department of Conservation, Jefferson City, Missouri, USA. Burger, L. W., Jr., M. R. Ryan, E. W. Kurzejeski, and T. V. Dai- deep litter, vegetation height between 20 and 100 ley. 1994. Factors affecting the habitat value of Conserva- cm, moderately high but patchy forb coverage, and tion Reserve Program lands for bobwhite in northern Mis- patchy grass and litter cover with little woody veg- souri. Pages 103-119 in M. Dicks and M. Monson, editors. Proceedings of the NC163 Post-CRP Land-use Conference. etation (Dechant et al. 2003). Creating such habitat Great Plains Agricultural Policy Center, Oklahoma State in Wisconsin, for example, which is well outside the University, Stillwater, Oklahoma, USA. breeding range of the species, is unlikely to provide Carroll, S. C., D. R. Rummel, and E. Segarra. 1993. Overwinter- ing by the boll weevil (Coleoptera: Curculionidae) in conser- any benefits to the species. Also, mowing grassland in vation reserve program grasses on the Texas high plains. September will have far different consequences than Journal of Economic Entomology 86:382-393.

40 The Wildlife Society Technical Review 07–1 September 2007 Dale, B. C., P. A. Martin, and P. S. Taylor. 1997. Effects Herkert, J. R., D. L. Reinking, D. A. Wiedenfeld, M. Winter, of hay management on grassland songbirds in J. L. Zimmerman, W. E. Jensen, E. J. Finck, R. R. Koford, Saskatchewan. Wildlife Society Bulletin 25:616-626. D. H. Wolfe, S. K. Sherrod, M. A. Jenkins, J. Faaborg, and Dechant, J. A., M. L. Sondreal, D. H. Johnson, L. D. Igl, C. M. S. K. Robinson. 2003. Effects of prairie fragmentation on Goldade, M. P. Nenneman, and B. R. Euliss. 2003. Ef- the nest success of breeding birds in the mid-continental fects of management practices on grassland birds: Baird’s United States. Conservation Biology 17:587-594. sparrow. Northern Prairie Wildlife Research Center, James- Herkert, J. R., D. W. Sample, and R. E. Warner. 1996. Manage- town, North Dakota, USA. www.npwrc.usgs.gov/resource/ ment of Midwestern grassland landscapes for the conserva- literatr/grasbird/bais/bais.htm. (Version 12AUG2004). tion of migratory birds. Pages 89-116 in F.R. Thompson Davison, W. B., and E. Bollinger. 2000. Predation rates on real III, editor. Management of Midwestern landscapes for the and artificial nests of grassland birds. The Auk 117:147-153. conservation of neotropical migratory birds. USDA Forest Delisle, J. M., and J. A. Savidge. 1997. Avian use and vegeta- Service General Technical Report NC-187. tion characteristics of Conservation Reserve Program fields. Horn, D. J. 2000. The influence of habitat features on grassland Journal of Wildlife Management 61:318-325. birds nesting in the Prairie Pothole Region of North Dakota. Dykes, S. 2005. Effectiveness of native grassland restoration Ph.D. Dissertation. Iowa State University, Ames, Iowa, USA. in restoring grassland bird communities in Tennessee. M.S. Horn, D. J., and R. R. Koford. 2000. Relation of grassland bird Thesis, University of Tennessee, Knoxville, Tennessee, USA. abundance to mowing of Conservation Reserve Program Eggebo, S. L., K. F. Higgens, D. E. Naugle, and F. R. Quamen. fields in North Dakota. Wildlife Society Bulletin 28:653-659. 2003. Effects of CRP field age and cover type on ring- Horn, D. J., R. R. Koford, and M. L. Braland. 2002. Effects of necked pheasants in eastern South Dakota. Wildlife Society field size and landscape composition on grassland birds in Bulletin 31:779-785. south-central Iowa. The Journal of the Iowa Academy of Evrard, J. O. 2000. The Conservation Reserve Program and duck Science 109:1-7. and pheasant production in St. Croix County Wisconsin. Wis- Hughes, J. P., R. J. Robel, and K. E. Kemp. 2000. Factors consin Department of Natural Resources. Report NR 183. influencing mourning dove nest success in CRP fields. Jour- Faaborg, J., M. Brittingham, T. Donovan, and J. Blake. 1993. nal of Wildlife Management 64:1004-1008. Habitat fragmentation in the temperate zone: a perspec- Hull, S. D., R. J. Robel, and K. E. Kemp. 1996. Summer avian tive for managers. Pages 331-338 in D. M. Finch and P. W. abundance, invertebrate biomass, and forbs in Kansas CRP. Stangel, editors. Status and management of neotropical The Prairie Naturalist 28:1-12. migratory birds. USDA Forest Service General Technical Johnson, D. H., and L. D. Igl. 1995. Contributions of the Con- Report RM-229. servation Reserve Program to populations of breeding birds Farrand, D. T., and M. R. Ryan. 2005. Impact of the CRP on in North Dakota. Wilson Bulletin 107:709-718. wildlife conservation in the Midwest. Pages 41-62 in J. Johnson, D. H., and L. D. Igl. 2001. Area requirements of Haufler, editor. Fish and Wildlife Benefits from Farm Bill grassland birds: a regional perspective. The Auk 118:24-34. Programs: update 2000-2005. The Wildlife Society, Wash- Johnson, D. H., L. D. Igl, and M. D. Schwartz. 1998. Effects of ington, D.C., USA. haying Conservation Reserve Program fields on breeding Frawley, B. J., and L. B. Best. 1991. Effects of mowing on birds. Paper presented at annual meeting of the Ecological breeding bird abundance and species composition in alfalfa Society of America, Baltimore, Maryland, USA. fields. Wildlife Society Bulletin 19:135-142. Johnson, D. H. 1980. The comparison of usage and availability Furrow, L. T. 1994. The influence of field age on mammalian measurements for evaluating resource preference. Ecology relative abundance, diversity, and distribution on Conser- 61:65-71. vation Reserve Program lands in Michigan. M. S. Thesis, Johnson, D. H., and M. Winter. 1999. Reserve design for grass- Michigan State University, East Lansing, Michigan, USA. lands: considerations for bird populations. Proceedings of Gehring, T. M., and R. K. Swihart. 2004. Home range and the George Wright Society Biennial Conference 10:391-396. movements of long-tailed weasels in a landscape fragment- Johnson, G. D., M. K. Perlik, W. P. Erickson, and M. D. Strick- ed by agriculture. Journal of Mammalogy 85:79-86. land. 2004. Bat activity, composition and collision mortality George, J. L. 1952. The birds on a southern Michigan farm. at a large wind plant in Minnesota. Wildlife Society Bulletin Ph.D. Dissertation. University of Michigan, Ann Arbor, 32:1278-1288. Michigan, USA. Johnson, G. D., W. P. Erickson, M. D. Strickland, M. F. Shep- Gould, J. H., and K. J. Jenkins. 1993. Seasonal use of Conser- herd, D. A. Shepherd, and S. A. Sarappo. 2002. Collision vation Reserve Program lands by white-tailed deer in east- mortality of local and migrant birds at a large-scale wind- central South Dakota. Wildlife Society Bulletin 21:250-255. power development on Buffalo Ridge, Minnesota. Wildlife Greenfield, K. C., L. W. Burger, Jr., M. J. Chamberlain, and E. Society Bulletin 30:879-887. W. Kurzejeski. 2002. Vegetation management practices on Kamler, J. F., W. B. Ballard, E. B. Fish, P. R. Lemons, K. Mote, Conservation Reserve Program fields to improve northern and C. C. Perchellets. 2003. Habitat use, home ranges, and bobwhite habitat quality. Wildlife Society Bulletin 30:527-538. survival of swift foxes in a fragmented landscape: conserva- Greenfield, K. C., M. J. Chamberlain, L. W. Burger, and E. W. tion implications. Journal of Mammalogy 84:989-995. Kurzejeski. 2003. Effects of burning and discing Conser- King, J. W., and J. A. Savidge. 1995. Effects of the Conserva- vation Reserve Program fields to improve habitat quality tion Reserve Program on wildlife in Southeast Nebraska. for northern bobwhite (Colinus virginianus). American Wildlife Society Bulletin 23:377-385. Midland Naturalist 149:344-353. Koford, R. R. 1999. Density and fledging success of grassland Hall, D. L., and M. R. Willig. 1994. Mammalian species com- birds in Conservation Reserve Program fields in North Da- position, diversity and succession in Conservation Reserve kota and west-central Minnesota. Studies in Avian Biology Program grasslands. The Southwestern Naturalist 39:1-10. 19:187-195.

Fish and Wildlife Response to Farm Bill Conservation Practices 41 Labisky, R. F. 1957. Relation of hay harvesting to duck nesting conservation value of bird communities with Partners in under a refuge-permittee system. Journal of Wildlife Man- Flight-based ranks. Auk 120:541-549. agement 21:194-200. Oetting, R. B. and J. F. Cassel. 1971. Waterfowl nesting on Leman, C. A. and M. K. Clausen. 1984. The effects of mowing interstate highway right-of-way in North Dakota. Journal of on the rodent community of a native tall grass prairie in Wildlife Management 35:774-781. eastern Nebraska. Prairie Naturalist 16:5-10. Olsen, R. A., and M. J. Brewer. 2003. Small mammal popula- Luttschwager, K. A., K. F. Higgins, and J. A. Jenks. 1994. Ef- tions occurring in a diversified winter wheat cropping sys- fects of emergency haying on duck nesting in Conservation tem. Agriculture, Ecosystems and Environment 95:311-319. Reserve Program fields, South Dakota. Wildlife Society Phillips, S. A., C. M. Brown, Jr., and C. L. Cole. 1991. Weeping Bulletin 22:403-408. lovegrass, Eragrostis curvula (schrader) Nees von Esen- Madison, L. A., T. G. Barnes, and J. D. Sole. 1995. Improv- beck, as a harborage of arthropods on the Texas high plains. ing northern bobwhite brood rearing habitat in tall fescue The Southwestern Naturalist 36:49-53. dominated fields. Proceedings of the annual conference of Renner, R. E., R. E. Reynolds and B. D. J. Batt. 1995. The impact the Southeastern Association of Fish and Wildlife Agencies of haying Conservation Reserve Program lands on productiv- 49:525-536. ity of ducks nesting in the prairie pothole region of North and McCoy, T. D., M. R. Ryan, L. W. Burger, Jr., and E. W. South Dakota. Transactions of the North American Wildlife Kurzejeski. 2001a. Grassland bird conservation: CP1 vs. and Natural Resources Conference 60:221-229. CP2 plantings in Conservation Reserve Program fields in Rich, T. D., C. J. Beardmore, H. Berlanga, P. J. Blancher, Missouri. American Midland Naturalist 145:1-17. M. S. W. Bradstreet, G. S. Butche, D. W. Demarest, E. H. McCoy, T. D., M. R. Ryan, and L. W. Burger, Jr., and E. W. Dunn, W. C. Hunter, E. E. Inigo-Elias, J. A. Kennedy, A. M. Kurzejeski. 2001b. Effects of conservation practice, mow- Martell, A. O. Panjabi, D. N. Pashley, K. V. Rosenberg, C. M. ing, and temporal changes on vegetation structure on Rustay, J. S. Wendt, and T. C. Will. 2004. Partners in Flight CRP fields in Northern Missouri. Wildlife Society Bulletin North American Landbird Conservation Plan. Cornell Lab 29:979-987. of Ornithology, Ithaca, New York, USA. McIntyre, N. E. 2003. Effects of Conservation Reserve Pro- Riffell, S. K, and L. W. Burger. 2006. Estimating wildlife re- gram seeding regime on Harvester Ants (Pogonomyrmex), sponse to the Conservation Reserve Program: bobwhite and with implications for the threatened Texas Horned Lizard grassland birds. Final Report for Solicitation Number FSA-R- (Phrynosoma cornutum). The Southwestern Naturalist 28-04DC: Estimating wildlife response to the Conservation 48:274-313. Reserve Program. U.S. Department of Agriculture, Farm McIntyre, N. E., and T. R. Thompson. 2003. A comparison Service Agency. Washington, D.C., USA. www.fsa.usda.gov/ of Conservation Reserve Program habitat plantings with FSA/webapp?area=home&subject=ecpa&topic=nra respect to arthropod prey for grassland birds. The American Risser, P. G. 1996. Summary: a new framework for prairie con- Midland Naturalist 150:291-301 servation. Pages 262-274 in F. B. Samson and F. L. Knopf, McMaster, D. G., and S. K. Davis. 2001. An evaluation of editors. Prairie Conservation: preserving North America’s Canada’s Permanent Cover Program: Habitat for grassland most endangered ecosystem. Island Press. Washington, birds? Journal of Field Ornithology 72: 195-210. D.C., USA. McMaster, D. G., J. H. Devries, and S. K. Davis. 2005. Grass- Rodenhouse, N. L., and L. B. Best. 1983. Breeding ecology of land birds nesting in haylands of southern Saskatchewan: vesper sparrows in corn and soybean fields. American Mid- landscape influences and conservation priorities. Journal of land Naturalist 110:265-275. Wildlife Management 69:211-221. Rodgers, R. D. 1999. Why haven’t pheasant populations in Merrill, M. D., K. A. Chapman, K. A. Poiani, and B. Winter. western Kansas increased with CRP? Wildlife Society Bul- 1999. Land-use patterns surrounding Greater Prairie- letin 27:654-665. chicken leks in northwestern Minnesota. Journal of Wildlife Ryan, M. R., L. W. Burger, Jr., and E. W. Kurzejeski. 1998. Management 63:189-198. The impact of CRP on avian wildlife: a review. Journal of Millenbah, K. F. 1993. The effects of different age classes of Production Agriculture 11:61-66. fields enrolled in the Conservation Reserve Program in Ryan, M. R. 2000. Impact of the Conservation Reserve Pro- Michigan on avian diversity, density, and productivity. gram on wildlife conservation in the Midwest. Pages 45-54 M. S. Thesis, Michigan State University, East Lansing, in W. L. Hohman and D. J. Halloum, editors. A comprehen- Michigan, USA. sive review of Farm Bill contributions to wildlife conserva- Morris, K. 2000. Avian abundance and diversity in CRP, crop tion. U.S. Department of Agriculture, Natural Resources fields, pastures, and restored and native grasslands during Conservation Service, Wildlife Habitat Management Insti- winter. Passenger Pigeon 62:217-224. tute, Technical Report, USDA/NRCS/WHMI-2000. Murray, L. D., and L. B. Best. 2003. Short-term bird response Ryan, M. R., R. A. Pierce, III, K. M. Suedkamp-Wells, and C. K. to harvesting switchgrass for biomass in Iowa. Journal of Kerns. 2002. Assessing bird population responses to graz- Wildlife Management 67:611-621. ing. Pages 16-34 in W. Hohman, editor. Migratory bird re- Noss, R. F., E. T. LaRoe, III, and J. M. Scott. 1995. Endangered sponses to grazing. U.S. Department of Agriculture, Natural ecosystems of the United States: a preliminary assessment Resources Conservation Service, Washington, D.C., USA. of loss and degradation. National Biological Service, Wash- Samson, F. B., and F. L. Knopf. 1994. Prairie conservation in ington, D.C., Biological Report 28. North America. BioScience 44:418-421. NRCS. 2002. Natural Resources Conservation Service Conser- Sauer, J. R., J. E. Hines, and J. Fallon. 2004. The North Ameri- vation Practice Standard and Specifications: Conservation can Breeding Bird Survey, results and analysis 1966-2003. Cover (Code 327). USDA NRCS, Washington, D.C., USA. Version 2004.1. USFS Patuxent Wildlife Research Center, Nuttle, T. J., A. Leidolf, and L. W. Burger. 2003. Assessing the Laurel, Maryland, USA.

42 The Wildlife Society Technical Review 07–1 September 2007 Sauer, J. R., S. Schwartz, B. G. Peterjohn, and J. E. Hines. 1996. The North American Breeding Bird Survey home page. Version 94.3. Patuxent Wildlife Research Center, Laurel, Maryland, USA. Selting, J. P., and L. R. Irby. 1997. Agricultural land use pat- terns of native ungulates in south-eastern Montana. Journal of Range Management 50:338-345. Svedarsky, W. D., R. L. Westemeier, R. J. Robel, S. Gough, and J. E. Toepher. 2000. Status and management of the greater prairie chicken Tympanuchus cupido pinnatus in North America. Wildlife Biology 6:277-284. Swanson, D. A., D. P. Scott, and D. L. Risley. 1999. Wildlife benefits of the Conservation Reserve Program in Ohio. Journal of Soil and Water Conservation 54:390-394. Toepfer, J. E. 1988. Ecology of the greater prairie chicken as related to reintroductions. Dissertation. Montana State University, Bozeman, Montana, USA. USDA. 2003. 2002 Farm Bill—Conservation Reserve Pro- gram—long-term policy interim rule. Federal Regis- ter, National Archives and Records Administration, Washington, D.C., USA. www.fsa.usda.gov/dafp/cepd/ CRP%20Final%20050803.pdf Veech, J. A. 2006a. Increasing and declining populations of northern bobwhites inhabit different types of landscapes. Journal of Wildlife Management 70:922-930. Veech, J. A. A comparison of landscapes occupied by increas- ing and decreasing populations of grassland birds. Conser- vation Biology 20:1422-1432. Wachob, D. G. 1997. The effects of the Conservation Reserve Program on wildlife in southeastern Wyoming. Ph.D. Dis- sertation. University of Wyoming, Laramie, Wyoming, USA. Warner, R. E., and S. L. Etter. 1989. Hay cutting and the survival of pheasants: a long-term perspective. Journal of Wildlife Management 53:455-461. Weber, W. L., J. L. Roseberry, and A. Woolf. 2002. Influence of the Conservation Reserve Program on landscape structure and potential upland wildlife habitat. Wildlife Society Bul- letin 20:888-898. Westemeier, R. L. and J. E., Buhnerkempe. 1983. Responses of nesting wildlife to prairie grass management in prairie chicken sanctuaries in Illinois. Pages 36-46 in R. Brewer, editor. Proceedings of the Eighth North American Prairie Conference. Western Michigan University, Kalamazoo, Michigan, USA. Winter, M., and J. Faaborg. 1999. Patterns of area sensitivity in grassland-nesting birds. Conservation Biology 13:1424-1436. Winter, M., D. H. Johnson, J. A. Shaffer, T. M. Donovan, and W. D. Svedarsky. How consistent are the effects of patch size and landscape composition on density and nest success of grassland birds? Journal of Wildlife Management. In Press.

Fish and Wildlife Response to Farm Bill Conservation Practices 43